Re: [PATCH v3 2/4] iio: adc: ad4691: add initial driver for AD4691 family

[David Lechner]

On 3/16/26 10:29 AM, Sabau, Radu bogdan wrote:
> 
> 
>> -----Original Message-----
>> From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
>> Sent: Friday, March 13, 2026 12:58 PM
>> To: Sabau, Radu bogdan <Radu.Sabau@xxxxxxxxxx>
>>
>>> +	u32 acc_mask[2] = { mask & 0xFF, mask >> 8 };
>>
>> This looks quite wrong. Is it for sure like two 32-bit stances per each mask
>> byte? If not, this should be __le16 acc_mask = cpu_to_le16(~BIT(...));
>>
> 
> Hi Andy,
> 
> Each acc_mask has its own register, therefore the u32 acc_mask[2] is
> intentional - since the regmap is configured with val_bits=32 - the 4-byte
> stride matches what regmap reads. However, I understand how this
> can be confusing for anyone reading the code, therefore I propose
> two ways for this :
> 
> 1. Keep regmap_bulk_write and add a comment above acc_mask explaining
> why u32 is used, although these register values are 8 bits.
> 2. Switch to regmap_multi_reg_write, which takes explicit (reg, value) pairs
> and sidesteps the ambiguity entirely.
> 
> Do you have a preference?

Since we already have a custom read/write functions to handle different
register sizes and the chip can read more than one consecutive register
at once, can we just call this a single register and add a special case
to ad4691_reg_read/write() to handle it? Then we can just do a regular
regmap_read/write() functions to access it as a single 16-bit value.